# Traumatic Brain Injury and Neck Trauma

## Introduction

Traumatic brain injury (TBI) is the leading cause of death in trauma patients under age 45. Neck trauma, whether blunt or penetrating, poses unique challenges due to the concentration of vital aerodigestive, vascular, and neurological structures within a compact anatomical space. General surgeons must be proficient in the initial management of TBI and the evaluation and operative management of neck injuries, particularly in settings without immediate neurosurgical or vascular surgical coverage.

## Traumatic Brain Injury

### Classification and Pathophysiology

| TBI Severity | GCS Score | Management |
|-------------|-----------|------------|
| Mild | 13–15 | Observation, CT if indicated |
| Moderate | 9–12 | ICU admission, CT, close monitoring |
| Severe | 3–8 | Intubation, ICP monitoring, neurosurgical consultation |

The Glasgow Coma Scale categorizes TBI severity as mild (GCS 13-15), moderate (GCS 9-12), or severe (GCS 3-8). Primary injury occurs at the moment of impact and includes contusion, axonal shearing, and vascular disruption; this damage is largely irreversible. Secondary injury develops over hours to days and includes cerebral edema, ischemia, herniation, and excitotoxicity. Prevention of secondary injury is the primary goal of TBI management. Normal intracranial pressure is 5-15 mmHg, and sustained ICP above 20-22 mmHg is associated with poor outcomes. Cerebral perfusion pressure, calculated as mean arterial pressure minus ICP, should be targeted at 60-70 mmHg. The Monro-Kellie doctrine states that the cranial vault has a fixed volume, and increases in brain parenchyma, blood, or cerebrospinal fluid must be offset by decreases in another compartment or ICP will rise.

### Types of Intracranial Hemorrhage

An epidural hematoma typically results from rupture of the middle meningeal artery following a temporal bone fracture. The classic presentation involves a "lucid interval" followed by rapid deterioration. On CT, it appears as a biconvex (lens-shaped) hyperdensity that does not cross suture lines. A subdural hematoma results from tearing of bridging veins between the cortex and dural sinuses. On CT, it appears as a crescent-shaped hyperdensity that crosses suture lines. Acute subdural hematoma greater than 10 mm in thickness or with midline shift greater than 5 mm requires surgical evacuation. Subarachnoid hemorrhage involves blood in the subarachnoid space, often from cortical vessel injury, and carries a risk of vasospasm. Intraparenchymal hemorrhage and contusions occur most commonly in the frontal and temporal poles due to contact with the bony ridges of the anterior and middle cranial fossae.

<image>CT scan illustrations showing the four types of intracranial hemorrhage - epidural hematoma (biconvex), subdural hematoma (crescent), subarachnoid hemorrhage, and intraparenchymal contusion - with key distinguishing radiographic features labeled</image>

### Initial Management of Severe TBI

Early intubation is indicated for GCS of 8 or less, with cervical spine precautions maintained. Hypoxia (SpO2 below 90%) doubles mortality and must be avoided. Hypotension (SBP below 90 mmHg) must also be prevented, as even a single episode increases mortality by 150%. Herniation syndrome is recognized by unilateral fixed and dilated pupil, contralateral hemiparesis, and Cushing's triad (hypertension, bradycardia, irregular respirations). Emergent temporizing measures for herniation include elevation of the head of bed to 30 degrees, short-term hyperventilation to PaCO2 30-35 mmHg, and osmotic therapy with either mannitol (1 g/kg IV bolus) or hypertonic saline (23.4% 30 mL or 3% 250 mL bolus). ICP monitoring is recommended for severe TBI (GCS 3-8) with an abnormal CT, with options including an external ventricular drain (the gold standard, which also allows therapeutic CSF drainage) or an intraparenchymal monitor.

### Surgical Indications in TBI

Epidural hematoma requires craniotomy and evacuation when thickness exceeds 15 mm, midline shift exceeds 5 mm, or GCS deteriorates. Subdural hematoma is treated with craniotomy or craniectomy when thickness exceeds 10 mm, midline shift exceeds 5 mm, or GCS decreases by 2 or more points. Decompressive craniectomy is considered for refractory intracranial hypertension (ICP above 25 mmHg) despite maximal medical therapy; the DECRA and RESCUEicp trials showed reduced mortality but increased rates of vegetative state and severe disability. Depressed skull fractures that are open or depressed greater than the full thickness of the skull require operative elevation.

### Medical Management of Elevated ICP

A tiered approach is used. Tier 1 includes head elevation to 30 degrees, sedation and analgesia, CSF drainage via EVD, maintenance of normothermia, and correction of coagulopathy. Tier 2 includes hyperosmolar therapy (mannitol or hypertonic saline), moderate hypothermia (35-36 degrees Celsius, which remains controversial), and CPP optimization. Tier 3 includes decompressive craniectomy, barbiturate coma (pentobarbital), and therapeutic hypothermia. Seizure prophylaxis with levetiracetam or phenytoin for 7 days following severe TBI reduces early post-traumatic seizures. Anticoagulation reversal is critical in patients on warfarin (using 4-factor PCC and vitamin K), DOACs (idarucizumab for dabigatran, andexanet alfa for factor Xa inhibitors), or antiplatelet agents (platelet transfusion remains controversial).

## Neck Trauma

### Surgical Anatomy

| Zone | Boundaries | Key Structures | Surgical Access |
|------|-----------|----------------|-----------------|
| I | Clavicles/sternal notch to cricoid cartilage | Proximal carotid, vertebral, subclavian vessels; thoracic duct; lung apex; esophagus; trachea; RLN | Difficult; may require sternotomy/thoracotomy |
| II | Cricoid cartilage to angle of mandible | Carotid arteries, jugular veins, pharynx, larynx, esophagus, vagus nerve | Most surgically accessible |
| III | Angle of mandible to base of skull | Distal ICA, vertebral arteries, CN IX–XII | Difficult; endovascular preferred |

The neck is divided into three zones. Zone I extends from the clavicles and sternal notch to the cricoid cartilage and contains the proximal carotid arteries, vertebral arteries, subclavian vessels, thoracic duct, lung apex, esophagus, trachea, and recurrent laryngeal nerves. Zone II extends from the cricoid cartilage to the angle of the mandible, is the most surgically accessible zone, and contains the carotid arteries, jugular veins, pharynx, larynx, esophagus, and vagus nerve. Zone III extends from the angle of the mandible to the base of the skull and contains the distal internal carotid artery, vertebral arteries, and cranial nerves IX through XII.

<image>Lateral anatomical illustration of the neck showing Zone I, Zone II, and Zone III boundaries with key vascular and aerodigestive structures labeled within each zone, including the carotid arteries, jugular veins, trachea, and esophagus</image>

### Evaluation of Penetrating Neck Trauma

Hard signs mandating immediate operative exploration include active hemorrhage, expanding or pulsatile hematoma, airway compromise, air bubbling through the wound, massive subcutaneous emphysema, and hematemesis. Soft signs warranting further workup include nonexpanding hematoma, dysphagia, hoarseness, hemoptysis, oropharyngeal blood, and nerve deficit. The modern approach uses CT angiography, which has replaced the traditional zone-based mandatory exploration algorithm for Zone II injuries. CTA-guided selective management is now standard for all zones in hemodynamically stable patients without hard signs. The "no zone" approach performs CTA of the neck and chest for all stable patients with penetrating neck wounds violating the platysma, and findings dictate further evaluation or intervention regardless of zone.

### Vascular Injuries

Carotid artery injuries are preferably repaired (primary or interposition graft) for accessible injuries in neurologically intact patients, with endovascular stenting increasingly used for Zone I and III injuries. Carotid artery injury with an established stroke remains controversial; ligation may be considered when the patient has a dense neurological deficit with complete occlusion. Vertebral artery injuries are often managed with angioembolization or observation, as operative exposure is difficult. Internal jugular vein injuries should be repaired if possible, though unilateral ligation is well tolerated.

### Aerodigestive Injuries

Laryngotracheal injuries in stable patients are evaluated with flexible laryngoscopy and CT. Operative repair involves primary closure, and tracheostomy may be required. Pharyngoesophageal injuries are diagnosed with CT (sensitivity 90-95% with oral contrast), esophagography, and esophagoscopy; the combined sensitivity approaches 100%. Esophageal repair consists of primary closure in layers within 24 hours of injury. Delayed diagnosis (beyond 24 hours) increases morbidity significantly and may require drainage procedures, diversion, or muscle flap buttressing.

### Blunt Cerebrovascular Injury (BCVI)

Blunt carotid and vertebral artery injuries occur in 1-2% of blunt trauma patients but are frequently missed. Screening is performed using the modified Denver criteria: cervical spine fracture involving the transverse foramen or C1-C3, Le Fort II/III fracture, basilar skull fracture through the carotid canal, diffuse axonal injury with GCS below 6, cervical seat belt sign with significant soft tissue injury, or near-hanging. | Biffl Grade | Description | Management |
| --- | --- | --- | --- |
| I | Intimal irregularity, <25% narrowing | Antithrombotic therapy |  |
| II | Dissection/intramural hematoma, >25% narrowing | Antithrombotic therapy |  |
| III | Pseudoaneurysm | Antithrombotic ± endovascular stenting |  |
| IV | Occlusion | Antithrombotic therapy |  |
| V | Transection | Endovascular or surgical repair |  |

The Biffl grading scale classifies injuries as Grade I (intimal irregularity), Grade II (dissection or intramural hematoma with greater than 25% narrowing), Grade III (pseudoaneurysm), Grade IV (occlusion), and Grade V (transection). Treatment involves antithrombotic therapy (antiplatelet or anticoagulation) to prevent thromboembolic stroke, and Grade III-V injuries may require endovascular intervention.

<image>Illustration comparing the Biffl grading scale for blunt cerebrovascular injury showing Grades I through V with cross-sectional vessel diagrams depicting intimal irregularity, dissection, pseudoaneurysm, occlusion, and transection</image>

## Key Clinical Pearls

Prevention of secondary brain injury is paramount: hypotension (SBP below 90 mmHg) and hypoxia (SpO2 below 90%) must be avoided at all costs in TBI patients. A single episode of hypotension doubles mortality in severe TBI, and aggressive resuscitation is paramount. The "no zone" CTA-based approach to penetrating neck trauma has largely replaced mandatory Zone II exploration in most trauma centers. Hard signs in penetrating neck trauma mandate immediate operative exploration regardless of zone or diagnostic workup. Blunt cerebrovascular injury should be screened for using the Denver criteria, as missed BCVI carries a stroke rate of up to 50%.

## References
1. Carney N, Totten AM, O'Reilly C, et al. Guidelines for the management of severe traumatic brain injury. 4th ed. *Neurosurgery*. 2017;80(1):6-15.
2. Bromberg WJ, Collier BC, Diebel LN, et al. Blunt cerebrovascular injury practice management guidelines: the Eastern Association for the Surgery of Trauma. *J Trauma*. 2010;68(2):471-477.
3. Biffl WL, Moore EE, Offner PJ, et al. Optimizing screening for blunt cerebrovascular injuries. *Am J Surg*. 1999;178(6):517-522.
4. Tisherman SA, Bokhari F, Collier B, et al. Clinical practice guideline: penetrating zone II neck trauma. *J Trauma*. 2008;64(5):1392-1405.